The future of human cat allergy treatment could be changing cats with food, vaccines, or gene editing.



Any cat lover who has seen an allergic friend react to a beloved pet knows the dark powers that lie in this luxurious feline fur. Within minutes, an allergic human exposed to a cat can begin to sneeze and wheeze. Watery, itchy eyes. The misery is obvious.

Solutions for people who want to be around cats despite allergies are labor-intensive, of questionable value, and sometimes defy common sense. How many emergency room visits would result if we all tried to give our cats frequent baths?

This predicament has sparked the imagination of researchers, who see a lucrative market for better solutions in a country with more than 50 million cats in more than 20 million homes. Some scientists are now taking a different approach to pet allergies. Rather than trying to change allergic humans or their environment, they are trying to change cats.

Purina started competing at the start of the pandemic with a cat food – Pro Plan LiveClear – which she says can reduce the protein most allergy sufferers respond to by 47% after three weeks.

“It truly is, in my vet’s mind, a groundbreaking and groundbreaking pet food,” said Kurt Venator, Chief Veterinarian at Purina. “We really think this will help cats and humans come together. “

Another Swiss-based research group is working on a vaccine against the offending protein, called Fel d 1. And a team from Indoor Biotechnologies in Virginia is exploring CRISPR gene editing techniques to eliminate the gene that makes Fel d 1. These two projects are years from completion.

Indoor Biotechnologies mainly detects, tests and purifies allergens. Martin Chapman, its CEO, had a long interest in feline allergens, but a bogus company that marketed hypoallergenic fake cats until about 2015 really caught his attention.

“It kind of established that there was a market for cats that would cost up to $ 7,000 each,” said Chapman, a former professor of medicine and microbiology at the University of Virginia.

While some cats may end up in shelters because owners with allergies couldn’t live with them, allergists have said there is no doubt that many often choose their cat over their own comfort. They said it’s rare for an allergic cat owner to abandon the cat or even banish it from the bedroom.

“I haven’t really seen any patients willing to get rid of their cats,” said Patrick Gleeson, allergist at Penn Medicine. Regarding the new cat food, he added, “I think there is a huge market for this product.

Venator said an allergic cat owner who participated in a Purina focus group said he bought a new sofa every six months so he could remove allergens from his home and keep his cat.

Cat allergies affect 10-20% of adults. Over 90% of them react to Fel d 1. About 5% of adults are allergic to dogs, but many substances are involved in these allergies. This makes modifying dogs a more complicated project. Researchers say allergies to furry animals are on the rise.

Fel d 1 is produced in the salivary, skin and anal glands of cats and is found in their tears. Cats spread it when cleaning themselves. It spreads throughout the house when they lose fur or dander. All cats make it, including hairless cats, although the amounts vary from cat to cat or even from day to day. Bruce Kornreich, director of the Cornell Feline Health Center, said there is evidence that unspayed male cats do more than neutered females or males. There is no such thing as a hypoallergenic cat.

And, there is no way to totally escape Fel d 1. He rides on people’s clothes to go to work and school. “It’s everywhere,” said James Wedner, allergist at Washington University in St. Louis. He once saw five people with allergies who worked in a brand new office building. None had cats. He tested the building for mold, cockroaches and mice and found nothing. Then he found “incredibly high levels” of Fel d 1. Other workers were bringing it, he said.

No one knows what role Fel d 1 plays in the cat’s body, so any effort to get rid of it must take into account the effect on cats. Kornreich said there had been speculation that Fel d 1 could protect the skin from pathogens. Another possibility is that it is involved in chemical signaling. Nicole Brackett, postdoctoral researcher at Indoor Biotechnologies, sequenced the genes that make Fel d 1 in 50 domestic cats as well as some big cats and wild cats. She said genes are not “well preserved” in domestic cats, a sign that they are probably not essential.

Purina says her tests show her food is safe.

LiveClear is already available in six varieties, including Weight Management, Seniors, and Sensitive Stomach. sells a 3.5-pound bag for $ 21.58. (A similarly sized bag of unspecialized cat food could cost less than $ 10.) The allergen-reducing kitten food will arrive in September, Venator said.

The company’s innovative approach began a decade ago when Ebenezer Satyaraj, a nutritional immunologist, learned that his daughter was allergic to cats. He discovered that chickens produce an antibody against Fel d 1 which can be found in their eggs. The company added the antibody to the cat food. The resulting food neutralized up to about half of the Fel d 1 produced by some cats.

This means that treated cats still produce Fel d 1, of course, so it doesn’t automatically mean people with allergies will feel better with them. However, Wedner said higher doses of an allergen usually cause more symptoms.

But Gleeson, who said Purina’s new food was “promising,” said doctors “don’t really know how much allergen reduction is needed to reduce symptoms.”

He said doctors often recommend getting rid of the cat – most patients won’t – or washing it weekly. “I haven’t spoken to patients who have actually done this,” he said. They can also get rid of carpets, vacuum frequently, and get a HEPA air purifier. And, they can try allergy shots. “This is another area where the evidence is not very good,” Gleeson said. Then there are the drugs.

Wedner led a small Purina-funded University of Washington study that found that some people with allergies could reliably detect the difference between blankets used by cats that ate LiveClear and cats that ate other foods. These heroic volunteers sat with the blankets for three hours in closed rooms designed for growing tomatoes. Their allergy symptoms were monitored every 15 minutes.

Wedner recently completed a larger study that used real cats in homes. It has yet to be released, so he could not release the full results, but he said “patients were doing better with food than they were without.”

He also said that patients not in the studies volunteered to say the food helped them.

Elizabeth Knighton, a veterinarian at City Cat Vets in Philadelphia, said her mother was allergic to cats. “Even though I wanted a cat my whole life, I didn’t have one until I was 11,” she said. Her mother did not allow the cat in her room and had to get the allergy shot. “She always used an inhaler,” Knighton said.

She mentioned the new Purina food to some customers. “Because it’s so new, I just don’t have any comments yet,” she said. “I would like to know if I recommend something that works. “

Saiba Animal Health, a Swiss company initially known as HypoPet, takes a very different approach. He is working on a vaccine that turns the cat’s immune system up against the Fel d 1 proteins. The company’s research showed that the investigational HypoCat vaccine reduced Fel d 1 in cat tears and reduced symptoms in 10 owners. allergic cats.

Saiba also hopes to produce a vaccine for dogs.

Kornreich said one of the concerns with this type of vaccine is a stray immune response. “There is always a concern that the immune system may be stimulated to start neutralizing things that are not the target of interest,” he said.

As for the genetic approach, Brackett, at Indoor Biotechnologies, achieved an efficiency of 55% in eliminating Fel d 1 in a cat cell line. It’s a good rate, she and Chapman said. “Cat cells are notoriously difficult to work with,” Brackett said.

The next step will be to see if they can reduce the allergen in the cat’s salivary glands. Then comes the more difficult part: figuring out how to administer the genetic treatment to embryos or adult cats. They will keep an eye on techniques being tested by other CRISPR researchers.

“It appears there is a significant hurdle for CRISPR at this time,” Chapman said.

Knighton, the Philadelphia vet, said she was more comfortable with the special food, which neutralizes Fel d 1 after the cat makes it, than with larger biological changes in cats. . “I’m very suspicious of anything that tells your body to attack something your body is making,” she said.


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